1. Field
The present disclosure relates to a photo detector, and more particularly, to a photo detector, which detects incident light by using a periodic arrangement of a single-layer graphene and a multi-layer graphene.
2. Description of the Related Art
There are photo detectors having a structure, in which heterogeneous metals are positioned at both ends of the photo detector. The photo detector has heterogeneous metal electrodes, so that a process, such as multi-stage photo lithography or lift-off, is additionally required.
There is a graphene photo detector using a flow of carriers generated when nanoparticles are inserted between the graphenes and light is radiated between graphene nanoparticles. The photo detector requires an additional process, in which a graphene phase needs to form the nanoparticles. Further, the photo detector is utilized as a limited photo detector for detecting only light of a specific wavelength responding to an interaction between the graphene nanoparticles.
Further, there is a photo detector, in which when electrodes are formed at both ends of a graphene and light is radiated to a boundary surface of the graphene and the electrodes in a vertical direction, a photo current flows between both electrodes. In this case, in the photo detector, a pair of electron and hole is generated in the graphene, which receives light, so that a current is generated. In the photo detector, light needs to be always radiated to the boundary surface of the graphene and the metal, and when light is radiated to both boundary surfaces of the graphene and the metal at the same time, currents having the same size flowing in opposite directions are generated at both sides, so that a sum of photo currents becomes zero.
In this respect, a photo detector, which is capable of avoiding forming heterogeneous electrodes and detecting an optical signal even in a situation where light is radiated to a boundary surface of a graphene and a metal, has been required.